HYDROCHARIDE^E 561 



the commencement of a lateral root beneath the growing point of 

 the plumule. 



Germination. The hard brittle seed-coat splits from the micro- 

 pylar end upwards, but often remains for a time entire at the opposite 

 end, seated on the tip of the cotyledon, but sooner or later the two 

 halves fall apart. The delicate colourless tegmen remains inside 

 the brown testa. The cotyledon quickly elongates, without any 

 considerable increase in thickness, to three-quarters to one inch, it 

 is semiterete, shallowly grooved above at the base, while the apex is 

 thinner and usually bent upwards ; colourless at first, but soon 

 becoming green like the foliage-leaves. The hypocotyl is coloured 

 like the cotyledon, and like it undergoes no striking change, merely 

 elongating somewhat. 



The leaves of the plumule soon bend downwards, and get longer 

 and somewhat broader, then: edges are separated at the base, and they 

 are sessile ; the apex is often spirally rolled ; they are traversed by 

 a stronger midrib and two to four lateral nerves, and their edges 

 have small forwardly directed teeth, so that they agree essentially 

 with the later foliage-leaves except in size. The intra- axillary scales 

 are rather longer than in the case of the cotyledon. 



The seedling lives at first on the nutriment stored in the coty- 

 ledon and hypocotyl ; it is not for some weeks that the lateral root 

 bores through the parenchyma on the side of the hypocotyl be- 

 neath the median line of the cotyledon. It is thread-like and 

 unbranched. 



Stem of the mature plant very short, stoloniferous. 



Leaves radical, sessile, linear-lanceolate, acute, serrate with 

 short, pungent, upwardly directed teeth, traversed by a midrib and 

 two to four weaker parallel nerves on either side, green, glabrous, 

 somewhat fleshy. 



A submerged perennial herb. 



BURMANNIACEJ:. 



Benth. et Hook. Gen. PI. iii. 455. 



Fruit and Seed. The ovary is inferior, three-celled, with 

 axile placentation, or one-celled with three parietal placentas. 

 Ovules minute, anatropous, very numerous on each placenta. 

 Fruit a capsule, crowned by the marcescent perianth, terete 

 or three-angled or three-winged, membranous ; dehiscing 



II. 00 



